According to scientific research, the earth has experienced extremes before including major periods of low temperature (ice age) and much, much higher levels of CO2 gas.
True, but there are other factors to consider such as the sun is gradually getting warmer over time as helium builds up in its core. The planet will act differently today than historically, because of such factors.
The earth was designed by our creator and He instructed us to be fruitful and multiply. Is it not possible that He has designed the earth to be able to handle our existence here until He returns?
Yes, absolutely. He has also given us brains so that we can figure out how to be good stewards of the planet. When fluorocarbons were depleting the ozone layer, people figured it out and changed to alternate substances. When particulates were harming people in American cities, Americans figured it out and cleaned up the air. Ditto for lead in petrol. Lead in the air was harming children, so it was removed from fuel. Carbon dioxide is just one factor of many for people to consider when designing machines.